[media] v4l: vb2-dma-contig: add support for scatterlist in userptr mode
This patch introduces usage of dma_map_sg to map memory behind a userspace pointer to a device as dma-contiguous mapping. This patch contains some of the code kindly provided by Marek Szyprowski <m.szyprowski@samsung.com> and Kamil Debski <k.debski@samsung.com> and Andrzej Pietrasiewicz <andrzej.p@samsung.com>. Kind thanks for bug reports from Laurent Pinchart <laurent.pinchart@ideasonboard.com> and Seung-Woo Kim <sw0312.kim@samsung.com>. Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Tomasz Stanislawski
Mauro Carvalho Chehab
Родитель
40d8b7669b
Коммит
e15dab752d
|
|
@ -11,6 +11,8 @@
|
|||
*/
|
||||
|
||||
#include <linux/module.h>
|
||||
#include <linux/scatterlist.h>
|
||||
#include <linux/sched.h>
|
||||
#include <linux/slab.h>
|
||||
#include <linux/dma-mapping.h>
|
||||
|
||||
|
|
@ -27,6 +29,8 @@ struct vb2_dc_buf {
|
|||
void *vaddr;
|
||||
unsigned long size;
|
||||
dma_addr_t dma_addr;
|
||||
enum dma_data_direction dma_dir;
|
||||
struct sg_table *dma_sgt;
|
||||
|
||||
/* MMAP related */
|
||||
struct vb2_vmarea_handler handler;
|
||||
|
|
@ -36,6 +40,44 @@ struct vb2_dc_buf {
|
|||
struct vm_area_struct *vma;
|
||||
};
|
||||
|
||||
/*********************************************/
|
||||
/* scatterlist table functions */
|
||||
/*********************************************/
|
||||
|
||||
|
||||
static void vb2_dc_sgt_foreach_page(struct sg_table *sgt,
|
||||
void (*cb)(struct page *pg))
|
||||
{
|
||||
struct scatterlist *s;
|
||||
unsigned int i;
|
||||
|
||||
for_each_sg(sgt->sgl, s, sgt->orig_nents, i) {
|
||||
struct page *page = sg_page(s);
|
||||
unsigned int n_pages = PAGE_ALIGN(s->offset + s->length)
|
||||
>> PAGE_SHIFT;
|
||||
unsigned int j;
|
||||
|
||||
for (j = 0; j < n_pages; ++j, ++page)
|
||||
cb(page);
|
||||
}
|
||||
}
|
||||
|
||||
static unsigned long vb2_dc_get_contiguous_size(struct sg_table *sgt)
|
||||
{
|
||||
struct scatterlist *s;
|
||||
dma_addr_t expected = sg_dma_address(sgt->sgl);
|
||||
unsigned int i;
|
||||
unsigned long size = 0;
|
||||
|
||||
for_each_sg(sgt->sgl, s, sgt->nents, i) {
|
||||
if (sg_dma_address(s) != expected)
|
||||
break;
|
||||
expected = sg_dma_address(s) + sg_dma_len(s);
|
||||
size += sg_dma_len(s);
|
||||
}
|
||||
return size;
|
||||
}
|
||||
|
||||
/*********************************************/
|
||||
/* callbacks for all buffers */
|
||||
/*********************************************/
|
||||
|
|
@ -122,42 +164,194 @@ static int vb2_dc_mmap(void *buf_priv, struct vm_area_struct *vma)
|
|||
/* callbacks for USERPTR buffers */
|
||||
/*********************************************/
|
||||
|
||||
static void *vb2_dc_get_userptr(void *alloc_ctx, unsigned long vaddr,
|
||||
unsigned long size, int write)
|
||||
static inline int vma_is_io(struct vm_area_struct *vma)
|
||||
{
|
||||
return !!(vma->vm_flags & (VM_IO | VM_PFNMAP));
|
||||
}
|
||||
|
||||
static int vb2_dc_get_user_pages(unsigned long start, struct page **pages,
|
||||
int n_pages, struct vm_area_struct *vma, int write)
|
||||
{
|
||||
if (vma_is_io(vma)) {
|
||||
unsigned int i;
|
||||
|
||||
for (i = 0; i < n_pages; ++i, start += PAGE_SIZE) {
|
||||
unsigned long pfn;
|
||||
int ret = follow_pfn(vma, start, &pfn);
|
||||
|
||||
if (ret) {
|
||||
pr_err("no page for address %lu\n", start);
|
||||
return ret;
|
||||
}
|
||||
pages[i] = pfn_to_page(pfn);
|
||||
}
|
||||
} else {
|
||||
int n;
|
||||
|
||||
n = get_user_pages(current, current->mm, start & PAGE_MASK,
|
||||
n_pages, write, 1, pages, NULL);
|
||||
/* negative error means that no page was pinned */
|
||||
n = max(n, 0);
|
||||
if (n != n_pages) {
|
||||
pr_err("got only %d of %d user pages\n", n, n_pages);
|
||||
while (n)
|
||||
put_page(pages[--n]);
|
||||
return -EFAULT;
|
||||
}
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static void vb2_dc_put_dirty_page(struct page *page)
|
||||
{
|
||||
set_page_dirty_lock(page);
|
||||
put_page(page);
|
||||
}
|
||||
|
||||
static void vb2_dc_put_userptr(void *buf_priv)
|
||||
{
|
||||
struct vb2_dc_buf *buf = buf_priv;
|
||||
struct sg_table *sgt = buf->dma_sgt;
|
||||
|
||||
dma_unmap_sg(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir);
|
||||
if (!vma_is_io(buf->vma))
|
||||
vb2_dc_sgt_foreach_page(sgt, vb2_dc_put_dirty_page);
|
||||
|
||||
sg_free_table(sgt);
|
||||
kfree(sgt);
|
||||
vb2_put_vma(buf->vma);
|
||||
kfree(buf);
|
||||
}
|
||||
|
||||
static void *vb2_dc_get_userptr(void *alloc_ctx, unsigned long vaddr,
|
||||
unsigned long size, int write)
|
||||
{
|
||||
struct vb2_dc_conf *conf = alloc_ctx;
|
||||
struct vb2_dc_buf *buf;
|
||||
unsigned long start;
|
||||
unsigned long end;
|
||||
unsigned long offset;
|
||||
struct page **pages;
|
||||
int n_pages;
|
||||
int ret = 0;
|
||||
struct vm_area_struct *vma;
|
||||
dma_addr_t dma_addr = 0;
|
||||
int ret;
|
||||
struct sg_table *sgt;
|
||||
unsigned long contig_size;
|
||||
|
||||
buf = kzalloc(sizeof *buf, GFP_KERNEL);
|
||||
if (!buf)
|
||||
return ERR_PTR(-ENOMEM);
|
||||
|
||||
ret = vb2_get_contig_userptr(vaddr, size, &vma, &dma_addr);
|
||||
if (ret) {
|
||||
printk(KERN_ERR "Failed acquiring VMA for vaddr 0x%08lx\n",
|
||||
vaddr);
|
||||
kfree(buf);
|
||||
return ERR_PTR(ret);
|
||||
buf->dev = conf->dev;
|
||||
buf->dma_dir = write ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
|
||||
|
||||
start = vaddr & PAGE_MASK;
|
||||
offset = vaddr & ~PAGE_MASK;
|
||||
end = PAGE_ALIGN(vaddr + size);
|
||||
n_pages = (end - start) >> PAGE_SHIFT;
|
||||
|
||||
pages = kmalloc(n_pages * sizeof(pages[0]), GFP_KERNEL);
|
||||
if (!pages) {
|
||||
ret = -ENOMEM;
|
||||
pr_err("failed to allocate pages table\n");
|
||||
goto fail_buf;
|
||||
}
|
||||
|
||||
/* current->mm->mmap_sem is taken by videobuf2 core */
|
||||
vma = find_vma(current->mm, vaddr);
|
||||
if (!vma) {
|
||||
pr_err("no vma for address %lu\n", vaddr);
|
||||
ret = -EFAULT;
|
||||
goto fail_pages;
|
||||
}
|
||||
|
||||
if (vma->vm_end < vaddr + size) {
|
||||
pr_err("vma at %lu is too small for %lu bytes\n", vaddr, size);
|
||||
ret = -EFAULT;
|
||||
goto fail_pages;
|
||||
}
|
||||
|
||||
buf->vma = vb2_get_vma(vma);
|
||||
if (!buf->vma) {
|
||||
pr_err("failed to copy vma\n");
|
||||
ret = -ENOMEM;
|
||||
goto fail_pages;
|
||||
}
|
||||
|
||||
/* extract page list from userspace mapping */
|
||||
ret = vb2_dc_get_user_pages(start, pages, n_pages, vma, write);
|
||||
if (ret) {
|
||||
pr_err("failed to get user pages\n");
|
||||
goto fail_vma;
|
||||
}
|
||||
|
||||
sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
|
||||
if (!sgt) {
|
||||
pr_err("failed to allocate sg table\n");
|
||||
ret = -ENOMEM;
|
||||
goto fail_get_user_pages;
|
||||
}
|
||||
|
||||
ret = sg_alloc_table_from_pages(sgt, pages, n_pages,
|
||||
offset, size, GFP_KERNEL);
|
||||
if (ret) {
|
||||
pr_err("failed to initialize sg table\n");
|
||||
goto fail_sgt;
|
||||
}
|
||||
|
||||
/* pages are no longer needed */
|
||||
kfree(pages);
|
||||
pages = NULL;
|
||||
|
||||
sgt->nents = dma_map_sg(buf->dev, sgt->sgl, sgt->orig_nents,
|
||||
buf->dma_dir);
|
||||
if (sgt->nents <= 0) {
|
||||
pr_err("failed to map scatterlist\n");
|
||||
ret = -EIO;
|
||||
goto fail_sgt_init;
|
||||
}
|
||||
|
||||
contig_size = vb2_dc_get_contiguous_size(sgt);
|
||||
if (contig_size < size) {
|
||||
pr_err("contiguous mapping is too small %lu/%lu\n",
|
||||
contig_size, size);
|
||||
ret = -EFAULT;
|
||||
goto fail_map_sg;
|
||||
}
|
||||
|
||||
buf->dma_addr = sg_dma_address(sgt->sgl);
|
||||
buf->size = size;
|
||||
buf->dma_addr = dma_addr;
|
||||
buf->vma = vma;
|
||||
buf->dma_sgt = sgt;
|
||||
|
||||
return buf;
|
||||
}
|
||||
|
||||
static void vb2_dc_put_userptr(void *mem_priv)
|
||||
{
|
||||
struct vb2_dc_buf *buf = mem_priv;
|
||||
fail_map_sg:
|
||||
dma_unmap_sg(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir);
|
||||
|
||||
if (!buf)
|
||||
return;
|
||||
fail_sgt_init:
|
||||
if (!vma_is_io(buf->vma))
|
||||
vb2_dc_sgt_foreach_page(sgt, put_page);
|
||||
sg_free_table(sgt);
|
||||
|
||||
fail_sgt:
|
||||
kfree(sgt);
|
||||
|
||||
fail_get_user_pages:
|
||||
if (pages && !vma_is_io(buf->vma))
|
||||
while (n_pages)
|
||||
put_page(pages[--n_pages]);
|
||||
|
||||
fail_vma:
|
||||
vb2_put_vma(buf->vma);
|
||||
|
||||
fail_pages:
|
||||
kfree(pages); /* kfree is NULL-proof */
|
||||
|
||||
fail_buf:
|
||||
kfree(buf);
|
||||
|
||||
return ERR_PTR(ret);
|
||||
}
|
||||
|
||||
/*********************************************/
|
||||
|
|
|
|||
Загрузка…
Ссылка в новой задаче